Atom Unit State Consistency in Fail-Operational Vehicle Switches

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Solution Overview

Problem

In autonomous vehicles, fail-operational systems face challenges in maintaining state consistency during handover from a primary to a secondary component, especially when the primary component fails, leading to potential safety risks due to inconsistent state updates and reliance on unreliable or time-consuming state retrieval methods.

Innovation Solution

A system comprising an atom unit, buffer, state keeping unit, and peripheral unit, where the atom unit receives and saves messages and states, initiates message sending, and updates states in a repository, ensuring consistent state storage and independent operation, even if the primary execution unit fails, using separate hardware and error detection mechanisms like voting logic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If states are read from the failing part, then state information is available, but reliability is compromised due to low reliability of the failing component

Engineering Contradiction:
Improvestate information availabilityVSAvoidstate data reliability
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The system separates state storage from execution by introducing a dedicated state keeping unit that independently maintains state information, isolating it from the failing execution unit. This segmentation ensures that state data reliability is not compromised by execution unit failures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary mechanism (the state keeping unit with atomic update operations) between the execution unit and external state storage. This intermediary ensures that only consistent, verified state updates are transferred, filtering out potentially corrupted data from failing components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If external state storage is used, then state consistency is improved, but there is a risk that states are not consistent with messages sent to peripheral devices due to timing gaps

Engineering Contradiction:
Improvestate consistencyVSAvoidstate update timing delay
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The system performs preliminary actions by maintaining a buffer of pending state updates and message transmissions. Before committing state changes to external storage, the system ensures all related messages are queued and will be sent, preventing timing gaps between state updates and peripheral communications.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where the system monitors the completion of message transmissions to peripheral devices before finalizing state updates in external storage. This feedback loop ensures that state consistency is maintained by verifying that all associated communications are complete before committing changes.

Inventive Principle:
Principle #23Feedback

3Loss of information

If states are requested from sensors and units during handover, then current vehicle states can be obtained, but time is lost which may compromise safety

Engineering Contradiction:
Improvecurrent state informationVSAvoidhandover delay time
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The system performs preliminary actions by pre-caching state information in the state keeping unit during normal operation, before failures occur. When handover is needed, this pre-stored state information is immediately available, eliminating the time delay of requesting states from sensors and units during the critical handover period.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If the fail-operational part is less complex with fewer parts, then reliability is improved, but functionality is reduced

Engineering Contradiction:
Improvesystem robustnessVSAvoidsystem functionality
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements a universal state keeping unit that serves multiple functions: maintaining state information during normal operation, providing consistent state data during handover, and ensuring state consistency across different execution units. This single component performs multiple critical functions, enabling the fail-operational part to maintain full functionality despite reduced complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3726384B1Method and system for preserving consistency of states during fail-operational context switch
Publication Date: 2022.01.05 BAYERISCHE MOTOREN WERKE AG
  • EP3726384B1 patent drawingFigure 1
  • EP3726384B1 patent drawingFigure 2
  • EP3726384B1 patent drawingFigure 3

AI summary

Provided is a system for updating one or more states relating to a message in a vehicle, the system comprising a first execution unit (104), a state keeping unit (106), and a peripheral unit (102), it is an object of the present invention to improve the reliability of the states. The object of the present invention is achieved by an atom unit (103) and a buffer, wherein the atom unit (103) is configured to carry out the steps: a) receiving a first signal (110) from the first execution unit (104), indicating the message and the states; b) saving the message and the states in the buffer; c) receiving a second signal (120) from the first execution unit (104), requesting the initiation of sending the message; d) sending (125) the message to the peripheral unit (102); and e) sending a third signal (135) to the state keeping unit (106) to update the states.